<template>
  <view>
    <slot
      :options="options"
      :data="dataList"
      :pagination="paginationInternal"
      :loading="loading"
      :error="errorMessage"
    ></slot>
  </view>
</template>

<script>
const events = {
  load: 'load',
  error: 'error',
}
const pageMode = {
  add: 'add',
  replace: 'replace',
}

const attrs = ['pageCurrent', 'pageSize', 'collection', 'action', 'field', 'getcount', 'orderby', 'where']

/**
 * uni-clientdb
 * @description uni-clientdb是一个数据库查询组件，它是对uni-clientdb的js库的再封装。
 * @tutorial https://uniapp.dcloud.net.cn/uniCloud/uni-clientdb-component
 * @property {String|DBCollectionString} collection 表名
 * @property {String|ClientDBActionString} action 云端执行数据库查询的前或后，触发某个action函数操作，进行预处理或后处理
 * @property {String|DBFieldString} field 查询字段，多个字段用 `,` 分割
 * @property {String} orderby 排序字段及正序倒叙设置
 * @property {String|JQLString} where 查询条件
 * @property {String} pageData = [add|replace] `add` 多次查询的集合, `replace` 当前查询的集合
 * @value add 多次查询的集合
 * @value replace 当前查询的集合
 * @property {Number} pageCurrent 当前页
 * @property {Number} pageSize 每页数据数量
 * @property {Boolean} getone = [true|false] 指定查询结果是否返回数组第一条数据，默认 false。在false情况下返回的是数组，即便只有一条结果，也需要[0]的方式获取。在true下，直接返回结果数据，少一层数组
 * @value true 返回数组第一条数据
 * @value false 返回类型是数组，即便只有一条结果
 * @property {Boolean} getcount 是否查询总数量
 * @property {Boolean} manual 是否手动加载数据，默认为 false，页面onready时自动联网加载数据
 * @value true 开启后需要手动加载数据
 * @value false 页面onready时自动联网加载数据
 * @event {Function} load 成功回调。如联网返回结果后，想修改下数据再渲染界面，则在本方法里对data进行修改
 * @event {Function} error 失败回调
 */
export default {
  name: 'UniClientdb',
  props: {
    options: {
      type: [Object, Array],
      default() {
        return {}
      },
    },
    collection: {
      type: String,
      default: '',
    },
    action: {
      type: String,
      default: '',
    },
    field: {
      type: String,
      default: '',
    },
    pageData: {
      type: String,
      default: 'add',
    },
    pageCurrent: {
      type: Number,
      default: 1,
    },
    pageSize: {
      type: Number,
      default: 20,
    },
    getcount: {
      type: [Boolean, String],
      default: false,
    },
    orderby: {
      type: String,
      default: '',
    },
    where: {
      type: [String, Object],
      default: '',
    },
    getone: {
      type: [Boolean, String],
      default: false,
    },
    manual: {
      type: Boolean,
      default: false,
    },
  },
  data() {
    return {
      loading: false,
      dataList: this.getone ? {} : [],
      paginationInternal: {
        current: this.pageCurrent,
        size: this.pageSize,
        count: 0,
      },
      errorMessage: '',
    }
  },
  created() {
    this._isEnded = false

    this.$watch(
      () => {
        const al = []
        attrs.forEach(key => {
          al.push(this[key])
        })
        return al
      },
      (newValue, oldValue) => {
        this.paginationInternal.pageSize = this.pageSize

        let needReset = false
        for (let i = 2; i < newValue.length; i++) {
          if (newValue[i] != oldValue[i]) {
            needReset = true
            break
          }
        }
        if (needReset) {
          this.clear()
          this.reset()
        }
        if (newValue[0] != oldValue[0]) {
          this.paginationInternal.current = this.pageCurrent
        }

        this._execLoadData()
      },
    )

    // #ifdef H5
    if (process.env.NODE_ENV === 'development') {
      this._debugDataList = []
      if (!window.unidev) {
        window.unidev = {
          clientDB: {
            data: [],
          },
        }
      }
      unidev.clientDB.data.push(this._debugDataList)
    }
    // #endif

    // #ifdef MP-TOUTIAO
    let changeName
    const events = this.$scope.dataset.eventOpts
    for (let i = 0; i < events.length; i++) {
      const event = events[i]
      if (event[0].includes('^load')) {
        changeName = event[1][0][0]
      }
    }
    if (changeName) {
      let parent = this.$parent
      let maxDepth = 16
      this._changeDataFunction = null
      while (parent && maxDepth > 0) {
        const fun = parent[changeName]
        if (fun && typeof fun === 'function') {
          this._changeDataFunction = fun
          maxDepth = 0
          break
        }
        parent = parent.$parent
        maxDepth--
      }
    }
    // #endif

    if (!this.manual) {
      this.loadData()
    }
  },
  // #ifdef H5
  beforeDestroy() {
    if (process.env.NODE_ENV === 'development' && window.unidev) {
      const cd = this._debugDataList
      const dl = unidev.clientDB.data
      for (let i = dl.length - 1; i >= 0; i--) {
        if (dl[i] === cd) {
          dl.splice(i, 1)
          break
        }
      }
    }
  },
  // #endif
  methods: {
    loadData(args1, args2) {
      let callback = null
      if (typeof args1 === 'object') {
        if (args1.clear) {
          this.clear()
          this.reset()
        }
        if (args1.current !== undefined) {
          this.paginationInternal.current = args1.current
        }
        if (typeof args2 === 'function') {
          callback = args2
        }
      } else if (typeof args1 === 'function') {
        callback = args1
      }

      this._execLoadData(callback)
    },
    loadMore() {
      if (this._isEnded) {
        return
      }
      this._execLoadData()
    },
    refresh() {
      this.clear()
      this._execLoadData()
    },
    clear() {
      this._isEnded = false
      this.dataList = []
    },
    reset() {
      this.paginationInternal.current = 1
    },
    remove(id, { action, callback, confirmTitle, confirmContent } = {}) {
      if (!id || !id.length) {
        return
      }
      uni.showModal({
        title: confirmTitle || '提示',
        content: confirmContent || '是否删除该数据',
        showCancel: true,
        success: res => {
          if (!res.confirm) {
            return
          }
          this._execRemove(id, action, callback)
        },
      })
    },
    _execLoadData(callback) {
      if (this.loading) {
        return
      }
      this.loading = true
      this.errorMessage = ''

      this._getExec()
        .then(res => {
          this.loading = false
          const { data, count } = res.result
          this._isEnded = data.length < this.pageSize

          callback && callback(data, this._isEnded)
          this._dispatchEvent(events.load, this.getone ? (data.length ? data[0] : undefined) : data)

          if (this.getone) {
            this.dataList = data.length ? data[0] : undefined
          } else if (this.pageData === pageMode.add) {
            this.dataList.push(...data)
            if (this.dataList.length) {
              this.paginationInternal.current++
            }
          } else if (this.pageData === pageMode.replace) {
            this.dataList = data
            this.paginationInternal.count = count
          }

          // #ifdef H5
          if (process.env.NODE_ENV === 'development') {
            this._debugDataList.length = 0
            this._debugDataList.push(...JSON.parse(JSON.stringify(this.dataList)))
          }
          // #endif
        })
        .catch(err => {
          this.loading = false
          this.errorMessage = err
          callback && callback()
          this.$emit(events.error, err)
        })
    },
    _getExec() {
      let exec = getApp().globalData.db
      if (this.action) {
        exec = exec.action(this.action)
      }

      exec = exec.collection(this.collection)

      if (!(!this.where || !Object.keys(this.where).length)) {
        exec = exec.where(this.where)
      }
      if (this.field) {
        exec = exec.field(this.field)
      }
      if (this.orderby) {
        exec = exec.orderBy(this.orderby)
      }

      const { current, size } = this.paginationInternal
      exec = exec
        .skip(size * (current - 1))
        .limit(size)
        .get({
          getCount: this.getcount,
        })

      return exec
    },
    _execRemove(id, action, callback) {
      const db = getApp().globalData.db
      const dbCmd = db.command
      if (!this.collection || !id) {
        return
      }

      const ids = Array.isArray(id) ? id : [id]
      if (!ids.length) {
        return
      }

      uni.showLoading({
        mask: true,
      })

      let exec = db
      if (action) {
        exec = exec.action(action)
      }

      exec
        .collection(this.collection)
        .where({
          _id: dbCmd.in(ids),
        })
        .remove()
        .then(res => {
          callback && callback(res.result)
          if (this.pageData === pageMode.replace) {
            this.refresh()
          } else {
            this.removeData(ids)
          }
        })
        .catch(err => {
          uni.showModal({
            content: err.message,
            showCancel: false,
          })
        })
        .finally(() => {
          uni.hideLoading()
        })
    },
    removeData(ids) {
      const il = ids.slice(0)
      const dl = this.dataList
      for (let i = dl.length - 1; i >= 0; i--) {
        const index = il.indexOf(dl[i]._id)
        if (index >= 0) {
          dl.splice(i, 1)
          il.splice(index, 1)
        }
      }
    },
    _dispatchEvent(type, data) {
      if (this._changeDataFunction) {
        this._changeDataFunction(data, this._isEnded)
      } else {
        this.$emit(type, data, this._isEnded)
      }
    },
  },
}
</script>
